Category Archives: Void Detection

How Do Voids Under Concrete Form?

When the ground under a concrete slab erodes away, it can cause a lot of problems. Homes with basements usually have the most problems, but voids can impact driveways, patios, sidewalks, and more. The erosion causes air pockets or voids to develop under the concrete slab, taking support away from the surface.

filling voids under concrete

Causes of Voids

There are several different reasons that a void can occur beneath your concrete. Most of the time, it isn’t due to erosion, but other factors. Some processes are fast, others can take years to cause problems.

Soil consolidation occurs over time. This occurs when loose soil under the concrete consolidates or sifts down. If the soil is not properly prepared by being tamped down, this can occur. When the soil consolidates, a void can form over time.

Settlement is a natural occurrence that happens over time. It can occur with new construction or with property that is a hundred years old. It all depends on the type of soil and the weather patterns. Heavy rains or flooding can cause the soil to settle faster than normal. If the settling soil is in a large enough area, it can allow erosion to occur. Settling soil sets the table for a problem, erosion makes it worse.

If water doesn’t drain correctly or there is new landscaping or other additions to the property, erosion can start after years with no problems. The water will run freely, washing out the soil and create a void under the concrete. The bigger the void, the more damage that can occur.

Solutions for Voids Under Your Concrete

commercial polyjackingYou don’t have to tear up your concrete to fix the problem of having a void. The best solution is polyjacking. A high-density polyurethane foam is injected through small holes into the voids. The foam expands, filling the void and sealing any cracks on the underside of the slab. The foam will not wash away and the slab is usable shortly after the foam is injected. Mudjacking is an alternative, but the sand-based grout can be washed away and you’re back to square one.

You’ll still need to take care of drainage problems, as they will continue to cause problems for your home or business. Make sure that water is draining correctly and away from the foundation or concrete area. The polyurethane foam won’t wash away, but the surrounding soil can erode. Let a company like Pro Foundation Technology assist you with waterproofing services.

Protect your property from foundation damage, trip and fall hazards, and sunken concrete by making sure the water is draining from your property. If you already have problems, let an expert like those at help you restore your concrete slab to the necessary height.

Restoring a Historic Building’s Foundation

Historic Building Foundations

Reasons for Foundation Failure in Historic Buildings

historic building foundations, restoring historic foundations, foundation restorationHistoric buildings, like all buildings, often develop problems with a foundation that is sinking or become unleveled over time. There are some special consideration in restoring historic building foundations. Older buildings are particularly prone to foundation failure for a number of reasons.

Unstable soils – After a period of time, soils beneath and surrounding a foundation may become more compacted, shift, or develop gaps. This may be caused by flooding, removal or addition of trees and landscaping features, or years of changing soil moisture and freezing/thawing patterns.

Improper water drainage – At times, historic buildings are built on old creek beds or new flood plains. Construction on adjacent properties or parking lots may have altered the flow of water toward the property. Over time, even weather patterns may require installation of better interior and exterior water drainage systems to prevent foundation damage.

Foundation materials – Many older foundations are built from bricks or stones with mortar that deteriorates over time or develop cracks allowing water to leak and damage the foundation.

Dirt floors – Often older foundations have dirt floors that are more likely to allow water to enter the basement and cause further damage to the foundation.

Signs of Foundation Failure at a Historic Property

Historic properties, like all properties, often display classic signs of foundation failure:

  • collapsed masonry walls
  • sloping floors
  • cracks in walls, floors, or ceilings
  • misaligned doors and windows

Because historic buildings may be somewhat fragile and have historical value, it is particularly important that you hire a foundation contractor with an established record working on historic buildings.

Overall Guidelines for Restoring a Historic Building

Memorial Union, historic foundation leveling, Polyurethane Concrete LevelingWhenever a historic building requires restoration, there are certain standards which must be followed:

  • Retain Original Function – The property must be used in its original function or be given a new use which reflects its original period.
  • Retain Original Design and Features – Materials, features, spaces, and spatial relationships from the property’s period will be kept and preserved.
  • Retain Original Appearance – Work to stabilize and conserve the property will be physically and visually compatible with the restoration period and documented for future research.
  • Use Original Materials – Materials, features, and finishes characteristic from other historical periods will be documented prior to their alteration or removal.
  • Use Original Craftsmanship – Distinctive materials, features, finishes, construction techniques, and craftsmanship of the restoration period will be preserved.
  • Repair, Don’t Replace – Deteriorated features from the restoration period will be repaired rather than replaced. If a feature is replaced, it will match the old in design, color, texture, and, where possible, materials.
  • Document Changes – Replacement of missing features will be documented to preserve the original history of the property.
  • Prevent Damage to Materials – Chemical or physical treatments will be implemented in the gentlest means possible to prevent damage to historic materials.
  • Protect Archeological Resources – Archeological resources affected by a project will be protected and preserved in place with as little change as possible.
  • Protect Original Design – Designs that were never implemented during the restoration period will not be constructed.

 Considerations When Restoring a Historic Foundation

Below are some of the key steps you should undertake when hiring a contractor to repair or replace the foundation on your historic structure.

Hire a Structural Engineer – It’s always a good idea to hire a structural engineer who specializes in historic building foundations or has some building experience with historic homes to determine how much of your foundation needs to be replaced. A structural engineer will determine the underlying issues and best solution to repair the foundation and resolve the problem.

Document the Details – Before doing foundation repair or any restoration on a historic building, it is important to document as many details as possible. Take pictures, do measurements, and write down details of everything you observe. This will ensure that the new foundation will look exactly like the old one.

Hire an Experience Foundation Contractor – Especially with a historic property, it is essential to hire an experienced foundation contractor to restore the foundation. They will know and follow the restoration guidelines and will make certain that you have the necessary insurance and permit. Because of their experience, they will have knowledge of historic materials and techniques and take extra precautions so that none of the structure collapses or experiences further damage. has been a family owned and operated business since 1978 and has an outstanding reputation in restoring foundations of both residential and commercial structures, including historic ones.

Choose Matching Materials – Often older structures will have a brick or stone foundation, so you want to salvage as many of the original bricks or stones as possible. Even if you replace the original foundation with a concrete one, you can do masonry on the outside to make the new foundation look like the original.

Waterproof the New Basement – As long as you are replacing the foundation, you might want a contractor to place drainage tiles along the perimeter of the foundation to waterproof the basement.’s parent company, Pro Foundation Technology does basement waterproofing.

Consider Related Projects – If you have an old staircase in the basement that cannot be used, hire someone to build a new one. It’s also a good time to check and replace any outdated electrical, plumbing, or drainage systems. Replacing the soil around the foundation with a quality black topsoil and grading it to a five-degree angle away from the foundation will to provide good exterior drainage.

Why is Best for Historic Foundations

ground penetrating radar, gpr, detecting holesThere are several compelling reasons why Polyjacking,com would be a first choice to lift, level, and restore a historic foundation:

  • Professional Experience – has professional experience lifting and leveling historic building foundations, including the historic Memorial Union at the University of Missouri and the 200-year-old Belle Meade Mansion in Nashville, TN.
  • Ground Penetrating Radar – uses ground penetrating radar (GPR) to detect holes and voids beneath historic foundations.
  • Hole and Void Repair – The polyjacking process fills in holes and voids beneath historic foundations, providing a strong and long-lasting solution without doing excavation.
  • Quality Products – uses on the finest materials from Earth Contact Products (ECP), the leading US-manufacturer of foundation repair products.
  • Quality Service – has an A+ rating with the BBB and has been awarded for super service by Angie’s List.

Contact Today!

The professionals at are experienced at lifting and leveling historic structures. We appreciate the extra considerations in working on a historic site and make the extra effort to preserve and protect its integrity. Whether you have a historic structure or are making history with a newer one, contact us today.

Historic Memorial Union Gets New Life with Polyurethane Foam

Memorial Union, Polyurethane Concrete LevelingWith its beautiful Gothic architecture and bell tower, the Memorial Union at the University of Missouri has been slowly deteriorating. This iconic building was built to honor the 117 Mizzou alumni who died in WWI. Due to soil erosion and severe dry conditions, voids and cavities formed beneath the surface. In turn, this caused the concrete slab to become uneven, becoming a significant threat to everything in its path.

A team of engineers, with structural design and environmental engineering experience, inspected the damage. They came to the conclusion that polyurethane foam would be more effective as opposed to using mudjacking. NCFI’s TerraThane Geotech foam system, the best in the spray foam industry, was used to repair the settlement. The area consisted of 1,200 sq. ft under the offices of the buildings and 1,500 lbs of TerraThane was injected into the surface. Unlike mudjacking, 5/8 inch holes were drilled into the surface without creating a mess. The process was quick, easy, effective, and didn’t require the building to be shut down during repairs. All of these factors played a major role in choosing polyurethane foam over traditional methods. Polyurethane fixed all soil issues without creating a burden onto the soil. This makes polyurethane a permanent solution for concrete leveling.

In conclusion, TerraThane costs 60% less than concrete replacement so it was the best choice for concrete leveling. Mark Whitehead, an experienced engineer, commented that “polyurethane played a major role in saving a building so important to the hundreds of thousands of Mizzou alums and future Tigers.”

Read more about the Historic Memorial Union project.

Did you know Missouri is a prominent place for sinkholes?

Distribution of sinkholes in Missouri

Sinkhole Distribution in Missouri

Did you know sinkholes are a common feature in Missouri? Most areas of Missouri are susceptible to sinkholes due to frequent exposure to water and the type of rocks underlying the soil. In fact, there are over 15,000 sinkholes in Missouri, and a lot more exist that are not reported or documented. If you are a homeowner or own property, it’s important to be aware of the development of sinkholes and the warning signs associated with them.

How do sinkholes develop? Sinkholes develop in karst terrains where the bedrock is dissolved by water. As it rains, water moves through cracks in the limestone and slowly dissolves the rock. Through this process, voids are formed and sinkholes develop on the surface. Over time, the voids become larger.  As they continue to grow, they structurally impact homes and buildings, causing serious foundation problems. In addition, sinkholes can occur on streets, parking lots as well in yards. Many sinkholes are circular, while others are not visible on the surface.

How To Control a Sinkhole in Missouri

Identify the Warning Signs
Unfortunately, sinkholes can develop over time or suddenly. They can form in all sizes, they can be deep or shallow, and can even be large or small. But the best way to identify sinkhole activity is to be aware of these common warning signs.

  • Zigzag wall cracks
  • Cracks located in the walls where windows and doors are present
  • Ceiling and wall separating
  • Depressions in your yard
  • New water puddles in the yard
  • Slumping trees, fence posts or other objects
  • Wilting vegetation
  • Hard to open or close windows and doors

Controlling the Sinkhole
If you notice a hole, secure the sinkhole by using warning tape or a rope to make sure people stay away from it. Next, fill the hole with sand, then monitor the hole and watch for changes in its size. Notify your insurance company, then contact a city inspection department or a professional engineer.

How are voids detected? In addition to being used for foundation repair and slab lifting, a ground-penetrating radar (GPR) will be used to detect voids developed from sinkholes. A GPR has many advantages over x-ray methods. It uses a benign electromagnetic pulse and a high frequency antenna to accurately locate voids. The GPR unit is portable to the site, making the process fast with instant results.

For more information about sinkholes and voids in the Missouri area, contact our team of experts.

Void Detection

What Causes Voids?

GPR void detection When voids form beneath the concrete, they can cause many issues such as settlement, cracking, and sinking foundations. These voids can form due to a number of reasons such as:

  • Soil Shrinkage – When there are periods of hot, dry weather, this will cause soil shrinkage forming voids beneath foundations and concrete.
  • Erosion – Excessive rainfall and melting snow will wash away the soil under your foundation and concrete creating voids.
  • Hydrostatic Pressure – Heavy precipitation can also lead to an increase in hydrostatic pressure in the soil creating voids and causing the foundation to shift, settle and sink.
  • Heaving and Settling – Varying temperatures will cause the ground to freeze and thaw, which will cause voids to form.

As a home or business owner, you may not even be aware these voids are occurring. This is why it is important to contact a professional with experience in void detection. can inspect your home or business using a ground penetrating radar (GPR) for void detection in Missouri and Kansas.

Using GPR to Find Voids

Void detection Kansas CityA GPR uses a high-frequency radar antenna and advanced signal software to accurately locate voids and objects. A GPR is fast, accurate and inexpensive. This method of void detection detects embedded utilities, conduit, pvc, rebar and tension cables. A GPR prevents costly and potentially dangerous mistakes, such as cutting utilities or rebar. It is a much quicker and less disruptive method than other void detection methods such as x-ray.

If voids are detected, we use high-density polyurethane foam to fill the voids. This polyurethane foam will expand to over 20 times its liquid volume to fill the entire void. The curing time is quick, so you can use the affected area immediately after the repair is completed. Poly trucks are used for the installation process. This method is relatively simple.

  1. A small 5/8″ hole is drilled through the affected area.
  2. Using our highly specialized system, polyurethane foam is injected into the void. As it expands, it fills the entire void.
  3. Lastly, the holes are filled, the site cleaned up and equipment removed.

Due to the short hardening time of the polyurethane material, the concrete surface is immediately ready for use. The dense polyurethane material is impervious to water preventing future erosion problems. Don’t let voids beneath your foundation or concrete cause you more expensive repairs. Contact the professionals at, a division of Pro Foundation Technology today!

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